Wireless communication devices capable of wireless communication even when attached to a metal surface of an article include a device disclosed in Patent Document 1 (identified below), for example.
The wireless communication device disclosed in Patent Document 1 includes a dielectric element body, an upper surface electrode disposed on an upper surface of the dielectric element body, and a lower surface electrode disposed on a lower surface of the dielectric element body and electrically connected to the upper surface electrode. These upper and lower electrodes are provided as one metal pattern extending from the lower surface to the upper surface of the dielectric element body. The upper electrode is provided with an opening and a slit extending from the opening to a side end of the electrode. Terminals of a wireless IC element are connected to each of facing portions of the slit.
A circumference of the opening functions as a loop electrode. When a high-frequency signal is received, a current is induced in the loop electrode, and the current is supplied through the facing portions of the slit to the wireless IC element. In this case, the loop electrode achieves impedance matching between the metal pattern and the wireless IC element.
Even when such a wireless communication device is attached on the bottom electrode side to a metal surface of an article, communication characteristics do not change. Therefore, the device can perform wireless communication whether it is attached to a metal surface of an article or not attached to the article.
Patent Document 1: Japanese Patent No. 5170156.